Status and Distribution of the Gapped Ringed Crayfish, Orconectes neglectus chaenodactylus, in Arkansas

Journal of the Arkansas Academy of Science Volume 64 Article 24 2010 Status and Distribution of the Gapped Ringed Crayfish, Orconectes neglectus chaenodactylus, in Arkansas Brian K. Wagner Arkansas Game and Fish Commission, C. A. Taylor Illinois Natural History Survey Mark D. Kottmyer The Nature Conservancy Follow this and additional works at: http://scholarworks.uark.edu/jaas Part of the Zoology Commons Recommended Citation Wagner, Brian K.; Taylor, C. A.; and Kottmyer, Mark D. (2010) "Status and Distribution of the Gapped Ringed Crayfish, Orconectes neglectus chaenodactylus, in Arkansas," Journal of the Arkansas Academy of Science: Vol. 64 , Article 24. Available at: http://scholarworks.uark.edu/jaas/vol64/iss1/24 This article is available for use under the Creative Commons license: Attribution-NoDerivatives 4.0 International (CC BY-ND 4.0). Users are able to read, download, copy, print, distribute, search, link to the full texts of these articles, or use them for any other lawful purpose, without asking prior permission from the publisher or the author. This Article is brought to you for free and open access by ScholarWorks@UARK. It has been accepted for inclusion in Journal of the Arkansas Academy of Science by an authorized editor of ScholarWorks@UARK. For more information, please contact , . Journal of the Arkansas Academy of Science, Vol. 64 [2010], Art. 24 Status and Distribution of the Gapped Ringed Crayfish, Orconectes neglectus chaenodactylus, in Arkansas B.K. Wagner1, C.A. Taylor2, and M.D. Kottmyer3 1 2 Arkansas Game and Fish Commission, 915 E. Sevier Street, Benton, AR 72015 Illinois Natural History Survey, Center for Biodiversity and Ecological Entomology, 1816 S. Oak, Champaign, IL 61820 3 The Nature Conservancy, 675 North Lollar Lane, Fayetteville, AR 72701 Correspondence: Abstract Orconectes neglectus chaenodactylus, the gapped ringed crayfish, is an uncommon and poorly-known, stream-dwelling crayfish that is endemic to the central White River basin of Arkansas and Missouri. This study surveyed a semi-random selection of stream sites in the Arkansas portion of this range in order to characterize the crayfish communities and evaluate the status of O. n. chaenodactylus in Arkansas. Collections of a total of 1,107 individual crayfish specimens were made at 45 sites, including 497 O. n. chaenodactylus from 21 sites. Orconectes punctimanus was the crayfish species most commonly associated with O. n. chaenodactylus, occurring at 71% of sites occupied by O. n. chaenodactylus. Orconectes n. chaenodactylus was found in streams not significantly different from the median characteristics of streams sampled in the study. It is our opinion that O. n. chaenodactylus is uncommon in Arkansas, and of only moderate concern due to its limited distribution in the state. Introduction The ringed crayfish, Orconectes neglectus, was originally described from Mill Creek in Wabaunsee County, Kansas (Faxon 1885). It is a medium-sized, stream-dwelling crayfish, typically growing to a total size of 30.5 – 96.5 mm (Pflieger 1996). It has broad, heavy chelae, a rostrum with a trough-like central depression, and male gonopods with two elongate, slightly curved processes (Pflieger 1996). The gapped ringed crayfish, Orconectes neglectus chaenodactylus, was recognized as a distinct subspecies based on specimens from White Creek in Douglas County, Missouri (Williams 1952). It differs from the nominate subspecies in having chelae with more slender fingers with a broad gap between the fingers and a smaller, shorter rostrum (Williams 1952). In addition to its long-standing recognition based on morphological characteristics, more recent genetic studies suggest the possibility that it is a distinct species (Crandall and Fitzpatrick 1996, Crandall 1998, Dillman et al. 2007). This crayfish is a tertiary burrower occupying cavities excavated under rocks seated in gravel and coming out at night to forage (Pflieger 1996). Price and Payne (1979) found females with eggs from midApril to mid-June in North Sylamore Creek, Stone County, Arkansas. They found the mean size at maturity to be 13.5 mm CL, based on the minimum size at which they observed a 50% probability of males being form-I, and observed that 50% reach this size during their first summer. Further, they noted adults molting 4 times in a year, in contrast to the standard expectation of 2 molts per year. Most adults live 2 to 3 years, with older individuals being rare. Price and Payne (1984a,b) observed young-of-the-year to appear in May in North Sylamore Creek and noted no gender differences in growth. O. n. chaenodactylus has a limited and poorly understood distribution. Original work suggested its endemism to the North Fork White River basin in Missouri (Williams 1954). It was first collected by 1967 in Arkansas (Robison 2002, Smithsonian lot USNM131642). Populations were originally thought to be restricted to the North Fork White River, and intergrades were hypothesized between it and O. n. neglectus throughout the remainder of the White River basin (Hobbs 1989, Pflieger 1996, Williams 1952). It has subsequently been reported from a few divergent locations in Arkansas, primarily in the North Fork White River and Sylamore Creek basins. It has recently been discovered, due to a suspected introduction, in the Spring River basin (Rabalais and Magoulick 2006). Taylor et al. (2007) considered it to be “vulnerable” and The Nature Conservancy ranks it as G5T3S2, meaning it is globally secure as a species, found locally in a restricted range as a subspecies, and very rare within the state. The objective of this study was to document the Journal of the Arkansas Academy of Science, Vol. 64, 2010 115 Published by Arkansas Academy of Science, 2010 115 Journal of the Arkansas Academy of Science, Vol. 64 [2010], Art. 24 B.K. Wagner, C.A. Taylor, and M.D. Kottmyer diversity and distribution of the crayfish fauna of the North Fork White and Middle White river basins in Arkansas and establish baseline distribution and status of O. n. chaenodactylus. Methods Study Area and Site Selection This study focused on the portions of the North Fork White and Middle White river basins in northern Arkansas. Based on the National Hydrology Dataset (NHD), these hydrologic units comprise 5,045 identified stream segments totaling 97,872 km. The Arkansas portion of these units includes parts of Baxter, Cleburne, Fulton, Independence, Izard, Searcy, Sharp, and Stone counties. Since these areas are largely in private ownership, road access to sampling sites was particularly important. U. S. Census Bureau data on roads in these counties was combined with the NHD data using ArcMap™ GIS software to identify stream segments intersected by roads. A random subset of these segments was selected for sampling by generating a random number between 0 and 19 as a start point, and then every 20th segment listed in the pooled list of accessible stream segments was (...truncated)